MTP joint focus: Capsulitis, Synovitis Bursitis: They sound similar so what’s the difference?
The Metatarsophalangeal joint (also known as the MTP joint) is a common site of inflammatory processes. Depending upon the area of involvement and site of primary disease process, MTP joint ailments can be classified as:
- Synovitis (inflammation of the tissues that line the joint i.e inflammation of the synovial membranes)
- Capsulitis (inflammation of ligaments surrounding the MTP joint i.e. inflammation of the joint capsule)
- Bursitis (inflammation of the bursa adjacent to the MTP joint)
These sound so similar. Whats the difference? How do you know if you have one and not the other?
Synovitis is inflammation of the tissues that line a joint causing increased fluid in the joint and even joint instability. In general Synovitis is commonly associated with specific diseases such as arthritis or gout, but may also be the result of overuse or trauma. Symptoms of synovitis may include redness, swelling, warmth, and pain with joint motion.
MTP synovitis frequently produces sharp aching pain that is most pronounced along the ball of the foot. The pain is usually suggestive of an ongoing disease process and usually involves the second metatarsophalangeal joint. The most common cause of MTP synovitis is repetitive stress on the metatarsophalangeal joint that results in persistent inflammation and resulting degeneration of tissues and ligaments that supports the base of toes. The stress is increased when the pressure on the ball of foot increases.
Common risk factors that may increase the risk of developing MTP synovitis are:
- Wearing high heels
- History of congenital or acquired lesions of foot; such as bunions or unusually long second toe
- Arch defects of the foot
- Rheumatoid arthritis
Some signs that are strongly suggestive of MTP synovitis are:
- Sharp pain in the ball of foot (mostly on the second toe).
- Aggravation of the pain when walking barefoot.
- Activity or walking on hard floors aggravates the pain.Other less common signs include; toes crossover and misalignment of 2nd toe.
Ligaments surrounding the joint at the base of the toe form a “capsule,” which helps the joint to function properly. Capsulitis is a condition in which these ligaments have become inflamed.
Although capsulitis can also occur in the joints of the third or fourth toes, it most commonly affects the second toe. This inflammation causes considerable discomfort and, if left untreated, can eventually lead to a weakening of surrounding ligaments that can cause dislocation of the toe.
Capsulitis is due to abnormal foot mechanics combined with repetitive foot motion that exerts pressure on the ball of foot to cause connective tissue degeneration. Poor foot dynamics or chronic stress can cause MTP capsulitis. Certain risk factors that may aggravate the risk of MTP capsulitis are:
- Tight or stiff calf muscles
- A second toe that is longer than your first toe
- An unstable pedal foot arch
- Chronic use of ill-fitting footwear (such as tapering toe-box or high heels)
- Formation of a large bunion
Classic sign and symptoms that are suggestive of MTP capsulitis are:
- Pain and swelling around the affected joint.
- Redness of skin overlying the affected joint surface.
- Sensation of walking on a pebble.
- Difficulty wearing shoes
Bursitis is inflammation and a painful swelling of a small sac of fluid called a bursa. Bursae (plural of bursa) are fluid filled cushions that help absorb shock and lubricate areas where tendons, ligaments, skin, muscles, or bones rub against each other. People who repeat the same movement over and over or who put continued pressure on a joint in their jobs, sports, or daily activities have a greater chance of getting bursitis.
The anatomical location of MTP bursa is at the base of metatarsophalangeal joint. Any condition that causes over-riding of metatarsal bones can aggravate the risk of developing bursitis as a result of tissue compression in the region.
Many cases of Morton’s neuroma present with adjacent bursitis and in some cases it can be very hard to differentiate the true cause of pain. In most cases, painful MTP bursitis involves first MTP joint. A bunion together with pain around the MTP joint is suggestive of MTP bursitis.
Certain risk factors that may aggravate the risk of MTP bursitis:
- A bunion (also called hallux valgus deformity) is associated with MTP bursitis due persistent rubbing and ongoing inflammation of bursa.
- Walking bare-foot or use of shoes with poor support can also lead to bursitis of metatarsophalangeal joint.
The classic presentation of MTP bursitis is:
- Persistent pain and discomfort that aggravates with the use of ill-fitting, narrow-mouth shoes.
- Palpable and often time visible swelling of bursitis which is painful to touch (in case of active inflammation).
- Weakness of tendons that are in direct communication of bursitis.
- Inability to move the involved MTP joint.
Untreated cases of large MTP bursitis can lead to rheumatoid arthritis and related degenerative types of joint dysfunction.
Regardless of the site of inflammatory process, the treatment protocols are similar. the key is to have a clinician experienced with diagnosing and treating these conditions.
Inflammatory lesions of MTP joint (synovitis, capsulitis, bursitis) usually responds to conservative therapies and surgery is not usually required in most cases. Most common interventions are:
- Rest and limitation of physical activities.
- Stretching is an ideal solution for individuals who develop MTP inflammation due to tight/ stiff calf muscles.
- Use of cold compresses or ice-wraps.
- Use of splinting helps in preventing unnecessary drifting of toes.
- If severe, you can use crutches or a cast in order to help heal the tissue in the short term.
- Over-the-counter anti-inflammatory medications are also helpful in reducing the intensity of inflammation and improving the quality of symptoms.
- Platelet Rich Plasma injections can be extremely helpful in the treatment of all joint inflammatory conditions.
- Although similar, there are subtle differences in the preferred treatment for these conditions. Specifically:
- Bursitis can be optimally treated with a Platelet Rich Plasma injection; and,
- Capsulitis can be treated with a corticosteroid injection initially and a Platelet Rich Plasma injection subsequently.
- However, if all conservative treatments fail to yield fruitful results, surgical intervention may be required as a last resort.
- Mazzuca, J. W., Yonke, B., Downes, J. M., & Miner, M. (2013). Flouroscopic Arthrography Versus MR Arthrography of the Lesser Metatarsophalangeal Joints for the Detection of Tears of the Plantar Plate and Joint Capsule A Prospective Comparative Study. Foot & ankle international, 34(2), 200-209.
- Hooper, L. (2011). Case Report. Bursae as a cause of forefoot rheumatoid pain in a patient with arthritis. Podiatry Now, 14(1).